1. Field of the Invention
This invention relates to a washing machine having a liquid pumping agitator, and more particularly to a washing machine wherein wash liquid is pumped outwardly through the interior of the agitator during the wash cycle.
2. Description of the Prior Art
Various attempts have been made at pumping wash liquid through the agitator of an automatic washing machine during the washing cycle. U.S. Pat. No. 2,542,733 discloses a pumping agitator with a flapper valve at the inlet to ram water from peripheral inlets through a screen to a central outlet opening. An alternative embodiment discloses utilizing centrifugal force to pump water outwardly through the agitator from the upper portion of the barrel.
U.S. Pat. No. 2,909,051 discloses a wash liquid pumping agitator in which the agitator travels through an orbital path as opened to rotating about a center axis and within the interior of the agitator there is provided a positive displacement pump which has an expanding and contracting chamber integrally connected with a cam arrangement to force the wash liquid upwardly through the agitator. Check valves are provided to maintain the flow of wash liquid up through the agitator in one direction.
U.S. Pat. No. 3,022,655 discloses a valveless pumping agitator which utilizes four spiral portions to ram wash liquid through inlet openings 26 upwardly through the spiral passage to the barrel of the agitator when the agitator moves in the clockwise portion of an oscillatory movement.
U.S. Pat. No. 3,091,954 discloses a positive displacement piston pump utilizing a fixed check valve and a floating check valve to pump wash liquid upwardly through the agitator as the agitator moves up and down in a reciprocating motion.
U.S. Pat. No. 3,145,553 discloses a vaned positive displacement pump which utilizes two sets of check valves to provide the wash liquid flow upwardly through the agitator to an agitator mounted filter.